Plumbers' supplies or similar & plumber in Wrocław

Is there an independent or small shop that sells sanitary/plumbers' supplies in the Borek/FAT/Karkonoska area of Wrocław? I need a sink drainage fitting (the screw in the trap or the whole trap). LM, Obi & similar do not stock the screw, only the entire part.

Also, what is the typical labour a Wrocław plumber may charge to come out and fit it if I cannot do it myself during the evening (18-19) please?

Thanks.

It looks something like this, however not exactly the same, but it's the metal screw that fixes the waste outlet to the plastic pipe underneath

Leroy Merlin at Karkonoska 85 should have it (the whole part - it's cheap and it will fit most of the sinks). Another shop for these kind of stuff is Castorama, but it's a little further away from the area you've mentioned.

There's no need for hiring a plumber.